64789domain: NAppears in sequencesComposite and every divisor (except 1) contains the digit 6.at n=18A062674Number of Golomb rulers of length n.at n=40A169942Expansion of 1/(1 - Sum_{k>=2} (1 - floor(2/d(k)))*x^k), where d(k) is the number of divisors (A000005).at n=50A280544